The whole "bolt-on horsepower" theme is a staple in enthusiast carmagazines because it sounds so enticing: just spin wrenches for a fewhours and, viola! Power beyond your wildest dreams.
Sadly, many products that try to pass as "bolt-on" are so difficult toinstall that the process becomes a tool-flinging exercise infrustration. Likewise, promised power gains often turn out to be farsmaller than advertised, leaving the once-hopeful tuner fed up with thepart, his car, and with the company that sold him the bill of goods inthe first place.
We're happy to report that the installation you see here is nothing likethat. It's the opposite, in fact. A&A Corvette Performance in Oxnard,California, took Vortech's LS1/LS6 supercharger kit and reengineeredsome key points to make it work even better.
The heart of the A&A Vortech...
The heart of the A&A Vortech supercharger system is Vortech's V-1 S-Trimcentrifugal supercharger. The case is cast from A356 aluminum alloy,heat treated and CNC machined. Impellers are also cast from aluminumalloy. The S-Trim blower can handle pressures up to 20 psi, though forthe high-compression LS6 application it's set up to produce about 7pounds of boost. The 10:1 LS1 application sees 9 psi. Did we tell youthe blower carries an E.O. number, too?
The biggest change involved the mounting point for the centrifugalsupercharger. Vortech's original design put it on the left (driver) sideof the engine, which meant the alternator and ABS box had to berelocated to make room for the case. By switching the blower position tothe right side of the engine, A&A eliminated any accessory relocation,which streamlined the installation process considerably.
That's not to say this kit just falls into the engine compartment. Asyou'll see in the accompanying photos, the process is straightforward,but there's enough to do here that the job required two days tocomplete, and that was with an A&A technician doing the work. A homemechanic or a shop not familiar with the job should allot even moretime.
For instance, to fit A&A's air-to-air intercooler into the enginecompartment, the radiator has to be removed, along with its supportbrace, and both must be relocated forward of their original position.Also, the A&A kit calls for pinning the crankshaft pulley, so the torquefrom the supercharger doesn't spin it right off the crank. The actualcrank pinning is simple enough, but accessing the pulley requires theremoval of the steering rack.
The end result, however, is well worth the effort. Using the streetableS-Trim V-1 supercharger pushing about 7 psi, the A&A Vortech systemadded 188.5 hp and more than 110 lb-ft of torque to this otherwisebone-stock Z06. The kit definitely packs a punch, but notice how thetorque curve stays nice and flat, and how the biggest change to thehorsepower delivery takes place after the LS6 spins through 3,000 rpm.That means the car is docile when you're puttering around town, butit'll pin you to your seat when you mash the gas pedal. If you seek evenbigger power gains, A&A can set you up with more-aggressive T- andJT-Trim superchargers. Got a C6? A&A is developing a similar system forthe LS2 as you read this.
What's the bad news? Even that isn't so bad. The complete A&A Vortechkit, including a new intake system, the intercooler, 42-pound fuelinjectors, and a bigger fuel pump, retails for $5,500. If you want A&Ato undertake the installation, bump up the price to $8,500, "and thatincludes every last nut and bolt, new spark plugs, and fresh oil," saysA&A's Andy Green. The house pours Mobil 1, of course.
 Here's a close-up view of...  Here's a close-up view of the 5/8-inch, CNC'd aluminum bracket A&A developed to mount the supercharger to the right side of the LS1/LS6. Doing so eliminates the need to relocate the alternator and ABS box. |  Look closely behind the blower...  Look closely behind the blower and you can see how a sliding idler pulley increases the wrap on the blower belt to the point where it's doubled back and almost touching itself. This greatly reduces belt slippage. |  A&A's air-to-air intercooler...  A&A's air-to-air intercooler is massive, yet it's lighter than the water-to-air 'cooler Vortech uses in its LS1 kit. Less weight over the nose is a good thing. Next to it is A&A's intake system, which uses a cleanable and reusable high-flow air filter. The piping for both the I/C and air filter is mandrel-bent steel, 3 inches in diameter between the supercharger and the I/C; and 4 inches from the I/C to the throttle body, and from the filter to the blower compressor. |